3 . material samples are tested by this system and software in the frequency rang of 8 - 12 ghz . finally , uncertainty has been analyzed and advanced methods for test 3 .在8 12ghz的頻率范圍內(nèi),利用研制的測(cè)量系統(tǒng)及軟件對(duì)樣品進(jìn)行了實(shí)驗(yàn)研究,對(duì)實(shí)驗(yàn)結(jié)果進(jìn)行了不確定度的分析,并針對(duì)實(shí)驗(yàn)遇到的情況提出了改進(jìn)措施。
The arcs representing grain interior conduction mechanisms appear on all complex impedance plots , and occur at high frequency rang and contract with temperature . however , those arcs representing grain boundary and occurring at low frequency range were observed only in a small number of experimental runs 而反映顆粒邊界導(dǎo)電機(jī)制的阻抗弧并不明顯,兩種阻抗弧出現(xiàn)在不同的頻率范圍內(nèi),反映顆粒內(nèi)部導(dǎo)電機(jī)制的阻抗弧出現(xiàn)在頻率較高的范圍內(nèi),而反映顆粒邊界導(dǎo)電機(jī)制的阻抗弧出現(xiàn)在頻率相對(duì)低的范圍內(nèi)。
For recent years , adsl has world widely employed and widely used in many aspects such as vod , remote medical treatment and e - shopping etc . but we noticed that the traditional telephone networks are designed for the transmission of low frequency signals , and the adsl ' s frequency rang is from 0 to 1 . 104mhz , so we must confront the signal attenuation , the loop line noise impairments , the crosstalk interferences , the bridge tap reflections and the rf disturbances problems and many other problems when transmitting the adsl signals one the telephone networks 近幾年來(lái), adsl在世界范圍內(nèi)得到充分的使用,廣泛應(yīng)用于視頻點(diǎn)播、遠(yuǎn)程醫(yī)療、網(wǎng)上購(gòu)物等各個(gè)方面。但是由于電話線網(wǎng)絡(luò)是專(zhuān)門(mén)為傳輸?shù)皖l信號(hào)而設(shè)計(jì),而adsl的頻譜范圍在0 1 . 104mhz內(nèi),因此在傳輸adsl信號(hào)時(shí),面臨著信號(hào)衰減、線路噪聲、串音干擾、橋接抽頭反射和射頻干擾等等多方面的問(wèn)題,這就要求在adsl開(kāi)通之前對(duì)線路進(jìn)行一系列的測(cè)試。